A method for treating lead pollution in water

Abstract

The present invention discloses a method for treating lead pollution in water, which comprises the following steps: Step 1, detecting the lead ion concentration of the water to be treated, adding hemin to the water to be treated and stirring and shaking to form a suspension; Step 2, filtering the suspension to obtain a filter residue and a clean aqueous solution after treating lead ions; Step 3, soaking the filter residue in an acidic solution to form an acidic suspension, and then filtering to obtain hemin and a lead-containing acid solution; Step 4, recycling hemin, and adding an excessive precipitant to precipitate and fix the lead ions after the lead ion concentration in the lead-containing acid solution reaches a preset threshold. The present invention can make the lead ion concentration in water reach an extremely low level by using hemin, and hemin can be recycled, without causing secondary pollution and reducing the treatment cost of lead ions.

Description

Technical Field

[0001] The present invention relates to the field of water pollution treatment, and specifically to a method for treating lead pollution in water. Background Art

[0002] Hemin is generally extracted from pig blood and has wide applications in the fields of medicine, food, chemical industry, health products, construction, and cosmetics. In the food industry, hemin can replace nitrite, a color fixative in meat products, and synthetic pigments; in the pharmaceutical industry, it can be used as a raw material for semi-synthetic bilirubin and can be used to prepare anti-cancer specific drugs; clinically, it can be made into a heme iron supplement; in the cosmetics industry, it is an important raw material.

[0003] As an iron fortifier, hemin has the advantages of high bioavailability, no iron accumulation poisoning in the body, and no adverse reactions such as gastrointestinal irritation. This is because hemin is absorbed in molecular form and can be directly taken up by the intestinal mucosa. Hemin is a bio-iron source recognized by modern medicine for the prevention and treatment of iron deficiency anemia, with high absorption rate and good effect. It has no iron smell and does not irritate the gastrointestinal tract, and is the first choice for iron supplementation and blood enrichment products for infants, pregnant women.

[0004] Among them, some people detect the lead poisoning situation of the human body by detecting the lead content of hemin in the human body, such as the paper "Determination of Trace Lead in Hemin by ICP - AES Method", etc. However, there is currently no method for treating lead in the environment with hemin. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for treating lead pollution in water to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A method for treating lead pollution in water, characterized by comprising the following steps:

[0008] Step 1: Detect the lead ion concentration of the water to be treated, add hemin to the water to be treated and stir and shake to form a suspension, and maintain it for 20 - 25 min; the molar ratio of lead ions to hemin is 1:2 - 3;

[0009] Step 2: Filter the suspension to obtain a filter residue and a clean aqueous solution after treating lead ions;

[0010] Step 3: Immerse the filter residue in an acidic solution with a pH not greater than 2 to form an acidic suspension, maintain shaking for 5 - 10 min; filter to obtain hemin and a lead-containing acid solution;

[0011] Step 4: Recycle hemin.

[0012] The described method for treating lead pollution in water is characterized in that a precipitant is added to the lead-containing acid solution to precipitate and fix lead ions.

[0013] The described method for treating lead pollution in water is characterized in that the precipitant is sodium carbonate or potassium carbonate.

[0014] The described method for treating lead pollution in water is characterized in that in step one, it is maintained for 20 min.

[0015] The described method for treating lead pollution in water is characterized in that the acidic solution is a strong acid solution; the strong acid solution includes hydrochloric acid solution, sulfuric acid solution, and nitric acid solution.

[0016] The described method for treating lead pollution in water is characterized in that in step one, the concentration of lead ions in water is detected by the spectrophotometer method.

[0017] The described method for treating lead pollution in water is characterized in that the spectrophotometer method is as follows: standard lead ion solutions with different concentrations are set, and then the absorbance at a wavelength of 283.15 nm is detected to obtain a standard curve of lead ion concentration versus absorbance; then the absorbance of the water to be treated is detected, and the lead ion concentration of the water to be treated is obtained according to the standard curve.

[0018] The described method for treating lead pollution in water is characterized in that the standard curve is y = 0.0005x + 0.0116.

[0019] The principle of the present invention is as follows:

[0020] Experimental treatment can be carried out under acidic and neutral conditions, and good capture of lead ions is achieved when the pH of the wastewater to be treated is between 3.5 and 7.2. When the pH is less than 3, there is a certain degree of desorption, which is not conducive to the capture of lead ions. Under weakly acidic or neutral conditions, lead in water mainly exists in the form of divalent lead ions (when the pH is less than 6, basically only divalent lead ions).

[0021] Hemin is insoluble in water. When hemin is poured into a certain aqueous solution and stirred and shaken thoroughly to form a suspension, the carboxyl groups of hemin have a certain hydrophilicity. Under sufficient oscillation, two carboxyl groups of hemin will combine with lead ions in water to form a complex, thereby capturing lead ions, and lead ions are desorbed and released under strong acid conditions. Description of the Drawings

[0022] Figure 1 This is the standard curve graph of the present invention. Detailed Embodiments

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] Example 1

[0025] The experiment we adopted was to directly weigh a certain amount of hemin and put it into a solution with a known lead content. The amount of substance of hemin was about 2 - 3 times that of lead ions in the sewage. Hemin is insoluble in water. At room temperature, under sufficient stirring, it can fully collide with lead ions in water and capture lead. Due to the rigid structure of heme porphyrin with a large molecular radius, it remains insoluble in water after capturing lead. Directly use filter paper for preliminary filtration and separation. At the same time, construct a standard system and set the concentration of the standard system preparation: 0, 50, 100, 150, 200, 250, 300 ug / L. Obtain the standard curve by using the spectrophotometric method. And prepare lead ion water samples to be treated with concentrations of 200 ug / L and 300 ug / L. Add 1.26 mg of hemin per liter to the 200 ug / L water sample and 1.89 mg of hemin per liter to the 300 ug / L water sample. Measure and compare the total lead content in the water before and after treatment. Initially set the treatment time to 20 minutes.

[0026] The standard curve is as Figure 1 shown. The lead ion concentrations of the standard solutions in the following steps are: 0, 50, 100, 150, 200, 250, 300 ug / L, and the measured absorbance values (average of three times) are: 0, 0.04, 0.074, 0.1, 0.124, 0.146, 0.165.

[0027] Concentration Absorbance 0 0 50 0.04 100 0.074 150 0.1 200 0.124 250 0.146 300 0.165

[0028] The standard curve is: y = 0.0005x + 0.0116, R = 0.9914

[0029] For the lead ion water samples to be treated with concentrations of 200 ug / L and 300 ug / L, the measurement and comparison of the total lead content in the water before and after treatment are as shown in the following table:

[0030] Before treatment After treatment Absorbance 0.123 0.043 Concentration (ug / L) 200 X1＝62.8 Absorbance 0.164 0.096 Concentration (ug / L) 300 X2＝168.8

[0031] According to national standards, the concentration after treatment needs to be lower than 100 ug / L. If the concentration is too high, the treatment time or the number of treatments can be increased. For a water sample with a concentration of 200 ug / L, which is 100% higher than the environmental pollution standard, we only need to act for 20 minutes to reduce the lead content in the aqueous solution to 62.8 ug / L. If the lead content is too high, multiple treatments can be carried out. Features: Heme is relatively easy to obtain, insoluble in water before and after treatment, and easy to recycle. Moreover, the treatment effect is extremely fast. For example, in 20 minutes, the lead content of 200 ug / L can be reduced to 68 ug / L, which is efficient, high-speed, green and recyclable. Chloride heme is relatively easy to obtain and relatively economical. Moreover, the heme ligand porphyrin ring has a rigid structure, a large radius and is relatively stable, which is convenient for recycling.

[0032] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for treating lead pollution in water, characterized in that, It includes the following steps: Step 1: Detect the lead ion concentration of the water to be treated by spectrophotometry. Add hemin to the water to be treated and stir and shake to form a suspension, and maintain it for 20 min. The molar ratio of lead ions to hemin is 1:2 - 3; Step 2: Filter the suspension to obtain the filter residue and the clean aqueous solution after treating the lead ions; Step 3: Immerse the filter residue in an acidic solution with a pH not greater than 2 to form an acidic suspension, and maintain shaking for 5 - 10 min. Filter to obtain hemin and the lead-containing acid solution. Add a precipitant to the lead-containing acid solution to precipitate and fix the lead ions; Step 4: Recycle hemin; The precipitant is sodium carbonate or potassium carbonate; the acidic solution is a strong acid solution; the strong acid solution includes hydrochloric acid solution, sulfuric acid solution and nitric acid solution; the spectrophotometry is as follows: Set standard lead ion solutions with different concentrations, then detect the absorbance at a wavelength of 283.15 nm to obtain the standard curve of lead ion concentration vs. absorbance. Then detect the absorbance of the water to be treated, and the lead ion concentration of the water to be treated can be obtained according to the standard curve. The standard curve is y = 0.0005x + 0.0116.

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